The present invention relates to a retractable cover system for an open top end container and wherein the system is operated by a drive train having a reversible electric motor drive whereby to pull the tarp over the container or retract it therefrom.
Retractable cover systems for open top end containers such as tractor trailers have been known for many years. It is also known to operate a cover such as a tarp to cover the open top end of these containers by motor drives and an example of these is illustrated in U.S. Pat. No. 3,829,154. Mechanical means for deploying the tarp and rewinding it on a drum is also taught by U.S. Pat. Nos. 3,977,719 and 4,995,663. These are only examples of existing systems but there are common problems in all of these retractable cover systems and namely that many of these do not adequately seal the open top end container against inclement weather conditions, the tarp often jams during deployment or retraction causing damage to the retractable cover system and adding cost to the operation. Furthermore, most manual systems are difficult to access and operate due to the large size of these tarps and they are also time-consuming. Another disadvantage is that the retractable cover system and particularly the guide members or associated hardware secured about the trailer becomes damaged by loading vehicles during loading and unloading of material within the open end container.
There is therefore the need to provide a retractable cover system which is fully automatic and reliable and which adequately shields the material within the open top end container from inclement weather.
It is therefore a feature of the present invention to provide a retractable cover system for open top end containers and which substantially overcomes the above-mentioned disadvantages of the prior art and fulfill the required need.
According to a broad aspect of the present invention there is provided a retractable cover system for open top end containers. The system comprises an elongated rectangular roll-up tarp wound on a drum. The drum is secured adjacent a top end of an end wall of a container. Guide channels are securable adjacent top edges of opposed side walls of a container for guidingly receiving therein a side seam portion provided on opposed longitudinal edges of the tarp. Each side seam portion has a pull cable immovably connected to a respective one of the longitudinal edges of the tarp. The pull cables extend beyond a free end edge of the tarp and are each guidingly displaceable by a respective guide member secured adjacent a rear corner of an opposed end wall of the container. The cables interconnect together at a predetermined connecting point spaced from the free end edge a distance greater than the length of the container. Pulling means is secured to the connecting point and wound on a drivable cable spool. The drum is mounted on a drive shaft. A drive train assembly is coupled to a reversible electric motor drive. The drive train assembly has a driven shaft rotatable by the electric motor in a clockwise or counterclockwise direction. An idle shaft is disposed parallel and spaced from the driven shaft. A pair of sprockets is secured to each the driven shaft and the idle shaft and aligned with one another and interconnected by a pair of endless sprocket chains. The sprockets on the driven shaft and idle shaft are secured to respective clutch assemblies. Each clutch assembly of the driven shaft is coupled to a respective linkage connected to a respective one of the drive shaft of the drum and the drivable cable spool whereby to drive one of said drum or said cable spool while idling the other and dependent on the drive direction of the electric motor whereby to pull the tarp over the open top end of the container or retract it therefrom.